PC started smoking, how to connect 6 fans

Mysterion04 · February 9, 2023

Hello hello, I'm building a new PC wich I do like 3 to 5 a year.
I bought the PC online, it was for a very good price and good components.. And i just make it more pretty and sell it again; Cablemod Cables, Vertical GPU Mounth, RAM cooler RGB etc..

Long Story short.. There are 6 Corsair SP120 RGB Corsair in the Case. They are only 3 Pins, plus another cable for the RGB HUB Controll. Havn't seen only 3 Pin Fans since a very long time. Normally i work with 4 Pin or Fans that comes with a HUB with remote controll where you can change speed and color.

So the thing is. The dude from which I bought the PC from had only 4 of those fans installed (he gave me 2 unused for free). And those 4 were seperated connected to the motherboard. And i don't wont that, cause like i said, You shouldnt see cables all around the place.

So I connected the fans to fan Splitters -

2 of those.. For all 6. But the fans were running at full speed all the time then obviously. and with 6 fans plus CPU Fan, it's to loud.

So I ordered this -

And connected my 6 fans to this and get the power from the sata cable. So you can switch the voltage/power for the fans. Off, Low or high. It had only good reviews.
I started the PC and after like 10 seconds the whole thing started to smoke.

And when i turned the switch to off, the rgb turned off too, even though the rgb stuff is on another cable.

I tested it with another one (bought 3) and connected just 1 fan to it.
It didnt smoke again but it was getting really really hot on the switch thing. So I will not use this stuff. At least not for those fans.

Any ideas why this happens to me? Maybe it works (better) for no rgb fans?

And how can i connect those fans that it doesnt run on fullspeed. I don't want it to connect seperat on my mainboard. And i don't even know if it has 6 fan pins.

Motherboard is MSI X470 Gaming Plus

Thanks for all your tipps already and sorry for my bad english

Ottoman420 · February 9, 2023

you might have fried something ether this fan controller or something else.

I think the corsair fans needed to be plugged in to a corsair fan and rgb hub

The sps i bought came with a commander pro and it didnt even work properly (flashing rgb) untill i got the new commander core or whatever and it works fine even with fan splitters plugged into it.

What have you plugged the sps rgb into?

https://www.corsair.com/uk/en/Categories/Products/Accessories-|-Parts/CORSAIR-iCUE-COMMANDER-CORE-XT-Smart-RGB-Lighting-and-Fan-Speed-Controller/p/CL-9011112-WW

Somethng like this allows you to control the corsair fans via corsair i cue and you can controll all fans individually as it also plugs into a usb 2.0 header on the motherboard.

Tristerin · February 9, 2023

Ive used that exact same hub with zero issues in builds but with generic fans

Could be faulty components in a batch they shipped. Those fans run at either 7v or 12v perhaps thats just a shitty resistor and its building up far to much heat resisting? What is LOW rated on the hub?

191x7 · February 9, 2023

Maybe 1 or more of those fans is faulty?

Those are 12V 0.3A fans.

The fan controller you've ordered uses only 1 12V from the Sata power and those are rated at a max of 1.5A (per 12V).

1.5A would be 5 fans if they were ideally at 0.3A but there's a chance of the fans needing a bit more or less.

I would not put more than 4 of those fans on a single controller like that. The SATA power cable might burn.

johnno23 · February 9, 2023

sounds like a voltage issue. fan cables if they have too high a voltage can rapidly heat smoke then melt. it is a simple thing to get wrong especially with many modern fans cables that want the 5v not a 12 volt. 12 v of some things as fans with a separate rgb 5v will just melt and burn within a matter of seconds if by accident put on a 12v line.

mariushm · February 9, 2023

It's not a current issue.

The SATA connector can supply 4.5A of current on 3.3v, 5v and 12v ... the fans consume around 0.1A .. 0.3A on 12v (maybe double this for a few seconds when they start spinning) so even with 6 fans connected to it the sata connector would be able to supply the amount of power.

The adapter seems to be using that slide switch to limit the voltage going to the fan by messing around to how the 12v and ground wires of the fans are connected to the sata connector.

I would guess HI speed means 12v goes to 12v in sata connector, ground to ground.

For LOW the switch may replace the ground with 5v, 12v and 5v becomes ground, so the fan "sees" 7v and spins slower... but some power supplies really don't like that, and on some models it can even damage the power supply internally.

On those Corsair fans, the 3 pin connector should be connected to such adapter, while the cable for rgb control should go to the proper fan controller.

Now here's the thing ... if inside the fan, the ground for the motor is joined together with the ground for the rgb leds, it could be that connector for rgb control has the ground wire connected to ground, but when you're switching that to LOW you're connecting the ground wire of the fan to 5v. So, basically, you're creating a short circuit between 5v and ground, and the weakest element in the chain will fail - either the trace on the circuit board going to the sata connector, or the thin ground wire of the fan...

Anyway, just guesses,

I would get a multimeter and with just the adapter connected to a sata connector, I would measure the voltage across the pins in each header, and see what voltage is when in LOW mode. Then measure voltage between a known ground point (ex the metal case of the computer or the middle wires in the old molex hard drive connectors) and the ground pin in the fan headers ... if you see 5v on that pin when the adapter is on LOW mode, then it's like I said above.